Hilton Worldwide and Marriott International are offering better discounts to loyalty club members in a bid to lower the amount of payments doled out to online third-party services, according to the The Wall Street Journal.

It's a trend that's likely to be followed across the industry as chains look to build stickiness with loyalty members.

Many hotel operators have contracts with sites such as Priceline and Expedia that limit their ability to undercut pricing, with the important exception of loyalty members.

With the DOJ having given its blessing to the deal yesterday afternoon, Expedia (EXPE+2.9%) has closed its $1.6B ($12/share) acquisition of Orbitz (OWW). The latter's shares have been delisted, while the former's are rallying for the second day in a row.

Expedia and Orbitz both jumped shortly before the close yesterday after Bloomberg reported U.S. regulators were set to approve the tie-up. The DOJ confirmed the report after the close, declaring it has "concluded that the acquisition is unlikely to harm competition and consumers."

Bloomberg reports U.S. regulators are set to approve Expedia's (EXPE+5.1%) $1.6B purchase of smaller rival Orbitz (OWW+6.4%). Shares of both companies have shot higher in response.

The DOJ has been closely vetting the deal, which has sparked complaints among travel industry firms about the post-merger company's dominant U.S. online travel share and potential pricing/bargaining power.

Update (4:26PM ET): The DOJ has released a statement confirming it won't challenge the Expedia/Orbitz deal. "The Antitrust Division investigated the concerns that have been expressed about this transaction. We took those concerns seriously and factored into our analysis all of the information provided by third parties. At the end of this process, however, we concluded that the acquisition is unlikely to harm competition and consumers."

Expedia (NASDAQ:EXPE) and Orbitz (NYSE:OWW) have both received a request for additional information related to the DOJ's antitrust review of Expedia's planned $1.6B acquisition of Orbitz. Naturally, the companies plan to "respond to the second request and to cooperate fully with the DOJ."

The deal, together with Expedia's planned $280M acquisition of partner Travelocity, has sparked fears within the industry Expedia will have an oversized position in the U.S. online travel market, thus giving it excessive leverage with hoteliers. Priceline has a larger share overseas.